As a result of the introduction of digitization and the internet, data such as e.g. pieces of music or feature films is being transmitted to an increasing extent in digitized form over distribution networks, such as e.g. the internet, to the respective end customers. A plurality of solutions exist which can be used for distributing the data or data streams.
Thus, with the aid of a centralized infrastructure the data stream can be routed by a broadcaster to a multimedia server which has a network link to the end customers and is responsible for forwarding the data stream to the end customers. In this case, where there is a large number of end customers, a hierarchical distribution scheme can be deployed with the aid of a plurality of multimedia servers in order to be able thereby to distribute the load and avoid imposing too heavy a load on a core network. A centralized infrastructure of the kind has the disadvantage that it is expensive to build and costly to maintain.
Another approach involves building overlay structures with and without distribution trees, which at least partially get by without a centralized infrastructure. Known methods are, for example, relaying methods via P2P networks (P2P—Peer2Peer), such as e.g. PeerCast. A disadvantageous aspect in this case is that the leaves of the distribution trees thus built make no further contribution to the broadcasting, i.e. to the distribution of the data stream. In this case the leaves represent out-and-out consumers. In a development of the overlay structures the data streams are split up into substreams, and the substreams are distributed by way of overlay structures, such as e.g. in a method by the name of SplitStream (see RFC 1889, “RTP—A Transport Protocol for Real-Time Applications”, Internet Engineering Task Force (IETF), at www.ietf.org.
The result of this extension is that all the nodes can be an internal node in one of the distribution trees and thus contribute bandwidth for overall distribution purposes. A disadvantageous aspect in this case, however, is maintaining the distribution trees, since complexity and susceptibility to faults are great due to the decentralized distribution of the tree structures, while a reorganization of the distribution trees in the event of a failure is costly and time-consuming and bridging failures by failover protection measures is difficult to implement since maintenance at the individual distribution trees is not centrally coordinated.